The International Olympic Committee announced today it will begin proceedings against 31 athletes who are believed to have violated anti-doping rules. None of the athletes have been individually identified, but the IOC says they span six sports and 12 different countries. Those athletes now face the possibility of being permanently banned from competing in Olympic Games, beginning with Rio in August. The 12 implicated national committees will be notified in the days to come.

The new doping results come just days after the former head of Russia’s official anti-doping laboratory admitted to swapping and destroying samples to protect athletes from negative test results. As many as 100 different samples were destroyed, implicating dozens of Russian athletes. The IOC subsequently began a rigorous campaign of retesting 454 previously collected samples from the London, Beijing, and Sochi games — a campaign Russia has supported. Today’s announcement comes partway through that process, with 250 results still to come.

“All these measures are a powerful strike against the cheats we do not allow to win,” said IOC president Thomas Bach in a statement. “They show once again that dopers have no place to hide.”